(1) Field of the Invention
This invention relates generally to audio and video components. More particularly, this invention relates to a laser and fiber optic apparatus connection audio source/preamplifier to audio speakers directly using optical fibers for transmission.
(2) Description of the Prior Art
Current conventional audio systems contain four major components: audio source, preamplifier, power amplifier and speakers. These components require different cables to connect each other. The components and connecting cables are listed below:
1. Audio Source:
A traditional audio source (e.g. turn table) has analog output only. A modern audio source (e.g. CD player) contains both analog and digital outputs. If the audio signals from a source are in digital form, an external digital-to-analog converter (DAC) must be added before the audio signals enter a preamplifier. Most audio sources don't have a volume control function. In this case, the volume/signal is controlled by a preamplifier. Some audio sources have volume control function to adjust the amplitude of output signals.
2. Preamplifier
The preamplifier has multiple signal I/Os with various types of connectors (e.g. RCA, XLR, BNC) and volume control function. The preamplifier amplifies the analog audio signals from audio sources or DAC and controls the volume of signals output to a power amplifier. The preamplifier also functions as a multiplexer for multiple input audio sources and multiple output power amplifiers.
3. Power Amplifier
The power amplifier is used to amplify the audio signals and push the signals to speakers. Considering that the amplified signals are easy to decay and the efficiency of speakers, the power amplifier needs to pump up the signals to huge amplitudes. It causes a large electrical current to carry the signals from power amplifier to speakers. In order to keep the signal loss and distortion low, the speaker cables should be as short as possible. Unfortunately, the speakers have to be located (far) away from the power amplifier in most cases. Therefore, the monoblock amplifiers were invented to put the power amplifiers close to speakers. The monoblock amplifiers still need speaker cables to connect speakers. The long signal cables between preamplifier and monoblock power amplifier can still cause significant signal loss and distortion.
4. Speaker
There are a lot of various designs for speakers. However, the speaker design is not in the scope of the invention. There are many types of speaker connectors for speaker cables. The spade and banana connectors are the most popular types.
5. Cables
The interconnect cables between signal source and preamplifier or between preamplifier and power amplifier are so-called signal cables. The cable between source and DAC is also a signal cable even though the signals are digital. The cables between power amplifier and speaker are speaker cables. Comparing with signal cables, the speaker cables need to bear high electrical current. The speaker cables are usually made with pure silver or copper for the high-end audio system.
The existing conventional connections for audio systems are shown in FIG. 1a prior art. First, in alternative (a) an audio source (CD. Player or turn table) 1 is shown having an analog output that is connected via signal cables 2 to a preamplifier 3 that is further connected via signal cables 2 to a power amplifier 4. The power amplifier is connected to speakers 6 via speaker cables 5. Second, in alternative (b) an audio source (e.g. CD Player) 7 is shown having a digital output that is connected via a signal cable 2 to a digital-to analog converter (DAC) 8 that is connected again via signal cables 2 to a preamplifier 3 that is further connected via signal cables 2 to a power amplifier 4. The power amplifier is also connected to speakers 6 via speaker cables 5. Third, alternative (c) illustrates a similar configuration as alternative (b) with the difference that instead of a single power amplifier 4, shown in (b), a monoblock amplifier 9 for each output channel of preamplifier 3 is deployed. The monoblock amplifiers can be deployed close to the speakers and make short speaker cables 5 possible. Similarly monoblock amplifiers could be used in alternative (a) as well instead of a single power amplifier 4.
As shown in FIG. 1a prior art, in a conventional audio system, the audio signals have to go through multiple components and cables from sources to speakers. Each component or cable can cause signal loss and distortion in various levels. It would be desirable to minimize signal loss and distortions between signal sources and speakers.
There are patents and publications known to keep signal loss and distortions low.
U.S. Patent Application Publication (US 2006/0093374 to Larson et al.) proposes a fiber optic communication signal link apparatus for performing fiber optic link communication including a transmitter apparatus and a receiver apparatus coupled by a fiber optic cable. The transmitter is capable of detecting and modulating data that includes at least one of position, light and audio data. An analog voltage signal representing the data is transmitted to the transmitter apparatus wherein the signal is detected, converted to a frequency signal and modulated through the fiber optic cable to the receiver apparatus. Subsequently, the frequency signal is detected, demodulated and converted back to a voltage analog signal in the receiver apparatus.
U.S. Patent Application Publication (US 2005/0276544 to Tsung-Ming Chen) discloses an optical digital audio system having an input receiver module that connects with one or multiple output speaker module(s) via optical fiber cable(s). The input receiver module has an audio signal receiving device, an amplifier and control device, one or multiple digital-to-optical converter(s), and one or multiple optical signal transmitter(s). The output speaker module has an optical signal receiver, an optical-to-digital converter, a digital signal amplifier, a digital-to-analog converter, and a speaker.
(U.S. Pat. No. 7,092,530 to Beer et al.) discloses a motor vehicle audio system having an audio signal receiver, an amplifier connected thereto via a fiber optic cable and a loudspeaker. A separate amplifier is provided for low audio signals. The amplifier is provided with a substantially higher line voltage when compared with the other audio frequency amplifiers.